The scrubbed Polish Mausers supplied to the Communist "Red Republicans" in the Spanish Civil War were scrubbed in Poland, not Czechoslovakia, although a few Czech VZ-24 rifles also went to Spain. Both the Polish and Czechs used the "Circle Z" marking, although the Polish version is often larger, the circle is more of an oval, and the Z sometimes has a European style crossbar in the middle. From what I have observed, SCW Polish Kar 98a's are more common than WZ-29's... and a lot of WW1 German made Kar 98a's were supplied to the Communists by Poland and to the Anti-Communist Nationalists by Germany. The WZ-29 is basically an upgraded Kar 98a, with a large ring receiver and more modern VZ-24 style stock - they both use the same identical barrel assembly. The Spanish M43 and M44 rifles use large ring receivers, not the small ring version used on the German and Polish versions of the 98a.
Many late production Polish Kar 98a rifles were originally outfitted with WZ-29 stocks at the factory, and many Polish, Spanish, and WW2 German refurbed Polish and German 98a's were outfitted with WZ-29 stocks....something to keep in mind here for anyone who might come across a sporterized German or Polish 98a, since original German and Polish 98a stocks and especially the handguards are a lot harder to find than a WZ-29 stock - which is not a common item either.
Considering the overall extremely high quality, general scarcity, and historical significance of the Polish Mausers, whether they remained in Europe (and ended up in German and Soviet hands) or went to Spain, these rifle are generally way underappreciated, undervalued, and unknown. Thus they make great bargains for the collector. The scrubbed versions go for a lot less than ones with intact Polish markings , but are no less historical or high quality.
I myself love Spanish Civil War Mausers and Mosins - every one I see gives me a warm fuzzy feeling as I think of dead Communists or the wretched, defeated Red rabble that survived to be literally "swept into the sea" by the victorious Nationalist forces, up to their armpits in the cold salt water with their arms raised in surrender. Being a Californian, I have dreams and visions of our own Red Filth, the California Legislature (and especially the Democrats in it) meeting a similar end in the Pacific Ocean.